Drug Summary

Atropine Sulfate (cardiac indications)

Pharmacologic properties:

Atropine is a potent parasympatholytic anticholinergic. It inhibits muscarinic receptor activity in the parasympathetic sites in smooth muscle, central nervous system, cardiac and secretory tissue. This reduces vagal tone, increases automaticity of the SA node and increases AV conductions, thus increasing heart rate. Additional effects include drying secretions and slowing motility in the gastrointestinal tract.


  • Bradydysrhythmias (rate < 50) accompanied by hemodynamic compromise, i.e. hypotension (systolic less than 90 mmHg), shock, pulmonary edema, altered level of consciousness
  • Pediatric Bradycardia (HR < 100 in an infant, HR < 60 in a child) despite adequate oxygenation, ventilation, chest compressions, and refractory to epinephrine


  • Atropine has no effect in patients with transplanted hearts
  • 3rd degree AV block in the setting of an acute anterior wall MI


  • If normal dose pushed too slowly, or if too small a dose (<0.5 mg) is given, heart rate may initially slow down
  • Atropine is potentiated by antihistamines and antidepressants
  • Cautious use in Type II AV block and 3rd degree block with wide QRS complexes

Adverse Reactions:

  • Restlessness
  • Agitation
  • Confusion
  • Pupil dilation
  • Blurred vision
  • Headache
  • Increased myocardial oxygen demand
  • Ventricular fibrillation
  • Dry mouth
  • Difficulty swallowing
  • Urinary retention

Dosage and administration:

  • Adult symptomatic bradycardia:
    • 0.5 mg IV bolus, repeat every 3-5 minutes until improved (maximum dose 3 mg)
  • Pediatric Symptomatic Bradycardia:
    • 0.02 mg/kg IV, IO or ET, (minimum individual dose is 0.1 mg and maximum individual dose is 0.5 mg)
    • May be repeated in 3-5 minutes
      • Maximum total dose 1.0 mg